Do you want to say gcc decides to check prototypes differently depending
on the location where it finds the files? I find that hard to believe.

From man gcc:
-Wsystem-headers
Print warning messages for constructs found in system header files.
Warnings from system headers are normally suppressed, on the
assumption that they usually do not indicate real problems and
would only make the compiler output harder to read. Using this
command line option tells GCC to emit warnings from system headers
as if they occurred in user code.
...
Hope it helps.
Ciao,
Wolfgang
--
Wolfgang%Solfrank.net@localhost Wolfgang Solfrank